cwr Posted January 18, 2020 Share Posted January 18, 2020 So I'm trying to figure out the neatest and easiest way to arrange the waste drains from one part of our build from a bathroom and ensuit. I'd like to minimise the IC's in the lower part of the drawing below as they're in a driveway, and like a lot of folk on here I'm not keen of exposed external pipework. First drawing here BC happy with, but I think would require an additional IC as four inlets coming in on one side? Two alternative options here, there are probably many more, maybe betters ways to do it. Green lines 50mm buried in the insulation, blue lines 110mm. By the way floor make up form top down is: 50mm screed, 170 PIR, 150mm concrete slab, DPM, sand, hardcore etc Please let share your thoughts and suggestions on these or other options, what's the best way to do it? Thanks. Link to comment Share on other sites More sharing options...
Temp Posted January 19, 2020 Share Posted January 19, 2020 It can be tricky to get the height and position of the WC pipes correct. If they are horizontal outlet pans you have to allow for screed and floor coverings which can vary. If vertical you have to position them the right distance from walls to allow for plastering, front to back depth of the cistern etc. All possible but it's a lot easier if you have stub stacks for the WC to connect to as you can adjust things later. You might also be able to connect other things into the stub stack reducing the number of connections into external IC Down side is you need to hide the stub stacks. One way to do that is to use concealed cistern as well and hide the lot in tiled studwork. Link to comment Share on other sites More sharing options...
PeterW Posted January 19, 2020 Share Posted January 19, 2020 Looking at that your architect has drawn those with exterior gully traps so is basically expecting external 40mm pipework which will look pretty crap tbh. I would look to improve those bathroom layouts tbh and use built in where possible. Link to comment Share on other sites More sharing options...
cwr Posted January 20, 2020 Author Share Posted January 20, 2020 OK, good point re the stub stacks, though i'm happy enough to get everything aligned. Yes I agree on external 40mm pipework, don't want any visible. How about this for an alternative? As before, blue line are 110mm below slab, green 50mm in insulation. 50mm connected onto toilet 110mm with a short boss connector. I take it's better practice to run 110mm below slab for the WHB, bath etc than 50mm in insulation? Link to comment Share on other sites More sharing options...
Temp Posted January 20, 2020 Share Posted January 20, 2020 (edited) We have 110mm under the slab coming up in the kitchen under the sink. 40mm waste pipes from sink and dishwasher connect into it via an adaptor. Is that big X a shower tray? You should plan how that will connect into the 110mm pipe carefully. You can get top access traps with a vertical outlet but I've never used one. If the hole in the tray isn't directly above the 110mm pipe it might help to know you can get adaptors/reducers that are non concentric. They are called "level invert" adaptors. Rotating one of these allows small errors in alignment to be corrected. Just had to do this on mine. How deep will your 110mm pipe be? I recall there is a minimum height for the lowest connection above the bottom of the 110mm. Looks like that would be the shower. I think you will need an AAV near the bath as the rush of water from the WC may suck water out of the basin, bath or shower traps. Edited January 20, 2020 by Temp Link to comment Share on other sites More sharing options...
Temp Posted January 20, 2020 Share Posted January 20, 2020 Thinking aloud... With a standard shower trap the pipework allows the trap to move vertically slightly when the tray is fitted and connected up. With a vertical outlet trap the height might be too rigidly fixed? Not a problem for a wet room but not sure how it would work for a tray that is bedded on mortar of unknown thickness. Sorry if I haven't explained that we'll. Link to comment Share on other sites More sharing options...
cwr Posted January 21, 2020 Author Share Posted January 21, 2020 Yes, you've explained that we'll enough for me to understand, thanks. Yes that's a shower. I had given some consideration to what would be needed to convert to a wet room in the future, so may as well put a wet room gully in from the start. AAV. Ok, I'll put a fitting in for one under the bath, or does it need to be higher up above spill over level? I think heights should be ok. 150mm from FFL to outside ground level, then min 300mm to top of pipe, 110mm dia pipe gives 560. Need 450 so there's some allowance for fall and depth of gully. Link to comment Share on other sites More sharing options...
Temp Posted January 21, 2020 Share Posted January 21, 2020 3 hours ago, cwr said: AAV. Ok, I'll put a fitting in for one under the bath, or does it need to be higher up above spill over level? Opinions vary. I believe it needs to be higher than the spillover of the lowest appliance so it doesn't reduce flood resistance of the property. However some say it must be higher than the spillover for the highest appliance for the same reason! That doesn't make sense to me. There are also "Type A" AAV that can be installed below the spill over level. Think they are rated for higher back pressures to keep water out in event of a flood. Link to comment Share on other sites More sharing options...
Oz07 Posted January 22, 2020 Share Posted January 22, 2020 Fitted a vertical waste with a shower tray yesterday. Was surprisingly hard to source the right bits. I though I was being clever bringing 110 up to exact centre of shower tray drain. Ended up cutting pipe approx 12mm lower than slab, fitting JT vertical waste with 90mm od body. Using a finned rubber off pan connector over waste body and lowered onto pipe greased up. I think those stack depths are for stacks. If you had a single connection on pipe it could be shallower. Link to comment Share on other sites More sharing options...
cwr Posted January 28, 2020 Author Share Posted January 28, 2020 (edited) Thanks for comments and suggestions. This is what I think I'll go with having given it some more thought and taken into consideration the above advice. I've also swooped the shower and hot press around, having been unable to remember why I had it the other way around. No doubt if there was some good reason it will come to me just as we're part way through and committed... I'll put an AVV under the bath (if BC are in agreement) and run the 50mm (green lines) in the insulation to make the shower tray fitting easier. Keeping the pipes under the wash hand basins accessible means that all pipe runs should be accessible for clearing should the need ever arrive. Edited January 28, 2020 by cwr Link to comment Share on other sites More sharing options...
PeterW Posted January 28, 2020 Share Posted January 28, 2020 25 minutes ago, cwr said: I'll put an AVV under the bath Don’t bother, just fit anti syphon traps to the basins in the EnSuite and the bathroom. If they insist on an AAV then run a 110mm tee under the corner of the hot press, reduce to 50mm and take it into the attic space and put it there. 1 Link to comment Share on other sites More sharing options...
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